Method for spraying chemical solution

Abstract

The present invention is directed to a method for spraying a chemical solution, including: spraying the chemical solution onto a dryer roller by a nozzle device with the nozzle device reciprocated along a rail extended in the width direction of the dryer roller, in a state that the dryer roller, for guiding wet paper, is being rotated, in a dry part of a paper-making machine, wherein a time T required for the nozzle device to travel one-way is set as 0.4 to 3.0 minutes; a rotational speed Vd of the dryer roller is set as not less than 100 times/min; the number of contacts N that a point Q on the dryer roller surface makes contact with the wet paper during the time T is set as 50 to 400 times; the time T, the rotational speed Vd, and the number of contacts N satisfy the relationship of N=T*Vd; and the total amount of the sprayed chemical solution is set as 0.3 to 500 mg/m2 as an effective component amount.

1 . A method for spraying a chemical solution, comprising: spraying the chemical solution onto a dryer roller by a nozzle device with the nozzle device reciprocated along a rail extended in the width direction of the dryer roller in a state that the dryer roller, for guiding wet paper, is being rotated, in a dry part of a paper-making machine,
 wherein a time T required for the nozzle device to travel one-way is set as 0.4 to 3.0 minutes;   a rotational speed Vd of the dryer roller is set as not less than 100 times/min;   a number of contacts N that a point on the dryer roller surface makes contact with the wet paper during the time T is set as 50 to 400 times;   the time T, the rotational speed Vd, and the number of contacts N satisfy the relationship of N=T*Vd; and   a total amount of the sprayed chemical solution is set as 0.3 to 500 mg/m 2  as an effective component amount.   
     
     
         2 . A method for spraying a chemical solution according to  claim 1 ,
 wherein an average moving speed Vn of the nozzle device is set as 4 to 10 m/min;   a paper width W of the wet paper is set as 4 to 12 m; and   the average moving speed Vn, the paper width W, and the time T satisfy the relationship of T=W/Vn.   
     
     
         3 . A method for spraying a chemical solution according to  claim 1 ,
 wherein a transportation speed Vp of the wet paper is set as not less than 600 m/min;   a diameter D of the dryer roller is set as 1.50 to 1.85 m; and   the rotational speed Vd, the transportation speed Vp, and the diameter D satisfy the relationship of Vd=Vp/πD.   
     
     
         4 . A method for spraying a chemical solution according to  claim 1 ,
 wherein the nozzle device is arranged to spray the chemical solution onto the dryer roller radially; and   a width of a sprayed portion on the dryer roller of the chemical solution sprayed instantaneously by the nozzle device is set as 1.5 to 9 cm.   
     
     
         5 . A method for spraying a chemical solution according to  claim 1 , wherein the wet paper contains recycled pulp at not less than 90% by mass. 
     
     
         6 . A method for spraying a chemical solution according to  claim 1 , wherein the chemical solution is an anti-soiling agent composition comprising at least one kind selected from the group consisting of amino modified silicone oil, epoxy modified silicone oil, polyether modified silicone oil, polybutene, a vegetable oil, and synthetic ester oil; and an absolute value of a zeta potential of the chemical solution is 3 to 100 mV.